Linux Deletion of SSL Certificate

name: Linux Deletion of SSL Certificate
id: 839ab790-a60a-4f81-bfb3-02567063f615
version: 12
creation_date: '2022-04-12'
modification_date: '2026-05-13'
author: Teoderick Contreras, Splunk
status: production
type: Anomaly
description: The following analytic detects the deletion of SSL certificates on a Linux machine. It leverages filesystem event logs to identify when files with extensions .pem or .crt are deleted from the /etc/ssl/certs/ directory. This activity is significant because attackers may delete or modify SSL certificates to disable security features or evade defenses on a compromised system. If confirmed malicious, this behavior could indicate an attempt to disrupt secure communications, evade detection, or execute a destructive payload, potentially leading to significant security breaches and data loss.
data_source:
    - Sysmon for Linux EventID 11
search: |-
    | tstats `security_content_summariesonly` count min(_time) as firstTime max(_time) as lastTime FROM datamodel=Endpoint.Filesystem
      WHERE Filesystem.action=deleted Filesystem.file_path = "/etc/ssl/certs/*" Filesystem.file_path IN ("*.pem", "*.crt")
      BY Filesystem.action Filesystem.dest Filesystem.file_access_time
         Filesystem.file_create_time Filesystem.file_hash Filesystem.file_modify_time
         Filesystem.file_name Filesystem.file_path Filesystem.file_acl
         Filesystem.file_size Filesystem.process_guid Filesystem.process_id
         Filesystem.user Filesystem.vendor_product
    | `drop_dm_object_name(Filesystem)`
    | `security_content_ctime(firstTime)`
    | `security_content_ctime(lastTime)`
    | `linux_deletion_of_ssl_certificate_filter`
how_to_implement: To successfully implement this search, you need to be ingesting logs with the process name, parent process, and command-line executions from your endpoints. If you are using Sysmon, you can use the Add-on for Linux Sysmon from Splunkbase.
known_false_positives: Administrator or network operator can execute this command. Please update the filter macros to remove false positives.
references:
    - https://www.sentinelone.com/labs/acidrain-a-modem-wiper-rains-down-on-europe/
drilldown_searches:
    - name: View the detection results for - "$dest$"
      search: '%original_detection_search% | search  dest = "$dest$"'
      earliest_offset: $info_min_time$
      latest_offset: $info_max_time$
    - name: View risk events for the last 7 days for - "$dest$"
      search: '| from datamodel Risk.All_Risk | search normalized_risk_object IN ("$dest$") | stats count min(_time) as firstTime max(_time) as lastTime values(search_name) as "Search Name" values(risk_message) as "Risk Message" values(analyticstories) as "Analytic Stories" values(annotations._all) as "Annotations" values(annotations.mitre_attack.mitre_tactic) as "ATT&CK Tactics" by normalized_risk_object | `security_content_ctime(firstTime)` | `security_content_ctime(lastTime)`'
      earliest_offset: 7d
      latest_offset: "0"
intermediate_findings:
    entities:
        - field: dest
          type: system
          score: 20
          message: SSL certificate deleted on host $dest$ by process GUID- $process_guid$
threat_objects:
    - field: file_name
      type: file_name
analytic_story:
    - AcidRain
    - AcidPour
asset_type: Endpoint
mitre_attack_id:
    - T1070.004
    - T1485
product:
    - Splunk Enterprise
    - Splunk Enterprise Security
    - Splunk Cloud
category: endpoint
security_domain: endpoint
tests:
    - name: True Positive Test
      attack_data:
        - data: https://media.githubusercontent.com/media/splunk/attack_data/master/datasets/malware/acidrain/sysmon_linux.log
          source: Syslog:Linux-Sysmon/Operational
          sourcetype: sysmon:linux
      test_type: unit